1- [bis(difluoroamino)fluoromethyl]-1, 2, 3, 3-tetrafluoroguanidine and process for preparing the same



United States Patent 3,361,815 1 [BIS(DIFLUOROAMINO)FLUOROMETHYL]- 1,2,3,3 TETRAFLUOROGUANIDINE AND PROCESS FOR PREPARING THE SAME John J. Hoekstra, Midland, Mich., assignor to The Dow Chemical Company, Midland, Mich., a corporation of Delaware No Drawing. Filed Aug. 31, 1962, Ser. No. 222,254 3 Claims. (Cl. 260-564) This invention relates to a novel chemical compound and more particularly is concerned with a new organic fluorine-nitrogen compound, l-[bis(difluoroamino)fluoromethyl]-l,2,3,3 tetrafluoroguanidine, corresponding to the formula:

This novel chemical compound is particularly suitable for use as a high energy oxidizing agent both in liquid and solid rocket propellant systems. The specific impulse of systems containing this material are markedly increased over that obtained using presently available fluorine containing oxidizers.

To illustrate; a substantially stoichiometrically balanced fuel-oxidizer rocket propellant system based on 1-[bis(difluoroamino)fluoromethyl]-l,2,3,3 tetrafluoroguanidine (herein designated as F BG), hydrazine and nitrogen tetraoxide exhibits a specific impulse of about 320.

This compound also can be used as a monomer reactant for polymerization into solid high energy oxidizers for use in solid rocket propellant systems. In this latter use, the compound can be directly polymerized or it can be copolymerized with other suitable polymerizable materials.

The compound is prepared by the direct low temperature fluorination of biguanide, biguanide sulfate or biguanide fluoride.

Conveniently F BG is produced by introducing gaseous fluorine diluted with an inert gas, e.g. nitrogen, with vigorous agitation and under substantially anhydrous conditions into an appropriate biguanide based material in a reactor maintained at a temperature of from about minus 25 C. to about 10 above zero centigrade. Ordinarily, the reactor temperature is maintained at from about 0 C. to about +5 C.

The product mixture is collected in a cold receiver, e.g. a cold trap cooled by Dry Ice-acetone or a Freon fluorocarbon slush bath, i.e. a slurry of a solid Freon fluorocarbon in liquid Freon fluorocarbon, maintained at a temperature of about minus 80 C. or lower. The F BG product readily is separated from the product mixture by distillation, codistillation, chromatography or other separation procedures. Both fractional codistillation and chromatographic techniques provide excellent means for recovering the compound.

Ordinarily, to aid in controlling the reaction rate, the biguanide based reactant is diluted with an inert, solid inorganic fluoride, such as the alkali or alkaline earth metal fluorides. Sodium fluoride alone or a mixture of sodium fluoride and magnesium fluoride have been found to be particularly useful diluents. The amount of inorganic fluoride used conveniently ranges from about 2 to about times or more the weight of the biguanide based reactant.

Although fluorine can be introduced directly into the reactor, desirably this reactant is employed in diluted form. A mixture of an inert gas, such as nitrogen, argon, etc., and fluorine wherein the amount of fluorine in the 3,361,815 Patented Jan. 2, 1968 mixture ranges from about 20 to about 40 percent on a volume basis is very satisfactory. This dilution range is not critical, however.

The ratio of fluorine and biguanide based material is not critical except that for optimum product yield, fluorine in excess of that stoichiometrically for the compound production is used. Any excess fluorine that is not reacted can be recovered from the eflluent product mixture exiting from the reactor and can be recycled for subsequent reaction.

The novel compound can be prepared in a batch type or continuou operation. Reactors and processing equip ment to be employed are fabricated from those materials which are not detrimentally affected by the reactants or product materials and which have the requisite physical strength and desired structural characteristics as is understood by one skilled in the art. Stainless steel, nickel, nickel alloys and the like all are suitable materials of construction.

The following example describes a method for preparing this compound but is not meant to be limiting.

Example-Preparation of 1- [bis(diflu0roamin0)fluoromethyl] -1,2,3,3-tetraflu0r0guanidine A mixture of fluorine and nitrogen gases comprising 1 part by volume fluorine and 2 parts by volume nitrogen at a flow rate of about 300 cubic centimeters per minute was passed into a stirred, substantially anhydrous mixture of about 5 grams biguanide sulfate, about 25 grams sodium fluoride and about 25 grams magnesium fluoride contained in a Monel nickel alloy reactor immersed in a cooling bath maintained at about 0 C. The reaction product mixture was collected in traps immersed in a Freon fluorocarbon slush bath at a temperature of from about minus 120 to minus 140 C. The collected product mixture was separated into its components by chromatographic techniques and the novel compound, l-[bis(difluoroamino)-fluoromethyl]-1,2,3,3 tetrafluoroguanidine recovered therefrom.

This compound was characterized as follows:

(1) Melting point: below 130 C.

(2) Molecular weight: experimental 268, theory 265 (3) Infrared spectra show N-F, CF, C=N bands and are consistent with the given structure.

(4) Mass spectrometry results are consistent with the molecular weight of 265 and the structure given for this compound.

(5) Nuclear Magnetic Resonance Data +126. 7 (doublet, 17 cps.)

+128.6 (triplet, 24 cps.)

These data confirm the structure of the compound.

These data also indicate the compound as produced is an approximate 50/50 mixture of romethyl -1,2,3,3-tetrafiuoroguanidine which comprises:

(a) passing a mixture of gaseous fluorine and nitrogen into a substantially anhydrous mixture of biguanide {TADS-(FINMCFNFC sulfate, sodium fluoride and magnesium fluoride 5 maintained at about C. said gaseous fiuorine-nitrogen mixture containing about 1 part by volume fiuoisomers. rine and about 2 parts by volume nitrogen and the N 0 combined weights of said sodium fluoride and mag- (6) Bolling point 80 nesium fluoride being about 10 times the Weight of In a manner similar to that described for the preceding Said biguanide lf t exanlple, biguanide and biguanide fluoride also can be 10 (b) collecting the efiluent reaction product mixture in fluormated to Produce FQBG. a receiver maintained at least at about minus 80 C.,

I claim: and The Compound 1j[l3i5(diflllomamino)fiuoromethyll' (c) separating said reaction product mixture into its 13,3,3-telrafiu0r0guan1dmecomponent parts to recover said l-[bis(difluoro- A PTOQCSS for P p g -l w mamino)fluoromethyl] 1,2,3,3 tetrafiuoroguanidiue romethyl]-1,2,3,3-tetrafluoroguanidine which comprises: th fr (a) passing fluorine into a substantially anhydrous References ci d member selected from the group consisting of biguanide, biguanide sulfate and biguanide fluoride at UNITED STATES PATENTS at temperature of from about minus C. to about 3,228,935 1/1966 Davis et 31 10 C., (b) collecting the reaction product mixture, and CHARLES PARKER Pnmm'y Exammer- (c) separating said l-bis(difluoroamino)fiuoromethyl]- L 11 ROSDOL E i 1,2,3,3-tetrafiuoroguanidine therefrom.

3 A process for preparing l [bis(difiuoroamino) fiuo 25 J. W. WHISLER. R. V. HINES, Assistant Examiners. 

1. THE COMPOUND 1-(BIS(DIFLUOROAMINO)FLUOROMETHYL)1,2,3.3-TETRAFLUROGUANIDINE.
 2. A PROCESS FOR PREPARING 1-(BIS(DIFLUOROAMINO)-FLUOROMETHYL)-1,2,3,3-TETRAFLUOROGUANIDINE WHICH COMPRISES: (A) PASSING FLUORINE INTO A SUBSTANTIALLY ANHYDROUS MEMBER SELECTED FROM THE GROUP CONSISTING OF BIGUANIDE, BIGUANIDE SULFATE AND BIGUANIDE FLUORIDE AT AT TEMPERATURE OF FROM ABOUT MINUS 25* C. TO ABOUT 10*C., (B) COLLECTING THE REACTION PRODUCT MIXTURE, AND (C) SEPARATING SAID 1-BIS(DIFLUOROAMINO)FLUOROMETHYL)1,2,3,3-TETRAFLUOROGUANIDINE THEREFROM. 